Obesity has become too normal in society and a "sugar tax" may be necessary in the long run, England's chief medical officer has said.

Dame Sally Davies used her annual report on the state of the nation's health to say too many people - and parents - may be ignoring the growing problem of obesity.

She said she had long been concerned that the fashion industry presented being underweight as an "ideal" aim.

"Yet I am increasingly concerned that society may be normalising overweight," she added.

"For example: larger mannequins are being introduced into clothes shops; 'size inflation' means that clothes with the same size label have become larger in recent decades; and news stories about overweight often feature pictures of severely obese people, which are unrepresentative of the majority of the overweight population."

Dame Sally said many people did not recognise they had a weight problem, with data showing that 52% of overweight men and 30% of overweight women think they are about the right weight.

Some 11% of obese men and 6% of obese women think the same, while 77% of parents of overweight children do not recognise their child is heavier than they should be.

And she said figures showed that between 2006/07 and 2012/13, some 27,860 children every year were found to be severely obese - on or above the 99.6th centile for weight.

This was putting them at increased risk of illness, including diabetes, asthma, musculoskeletal problems and heart disease.

Dame Sally said adults and children consumed more sugar than they should, with a third of added sugar in the diet of 11 to 18-year-olds coming from fizzy drinks, smoothies, and fruit juices with added sugar.

"This is an alarming proportion; soft drinks are easily avoidable sources of added sugar," she said, adding that clear labelling would help increase public understanding.

And Dame Sally reiterated her view that a "sugar tax" may be needed - something she told MPs earlier this month when she said she believed "research will find sugar is addictive".

Her views clash with those of the Government, which has taken the approach of asking manufacturers and food giants to sign up to voluntary codes with the aim of avoiding legislation on the issue.

In her report, Dame Sally said: " I call on manufacturers to ramp up reformulation of products to use less added sugar.

"If voluntary efforts fail to deliver then we, as a society, may need to consider the public health benefits that could be derived from regulation such as a 'sugar tax'."

Dame Sally also said far too few people did enough exercise, with recommendations being a minimum of 150 minutes (2.5 hours) of moderate intensity activity per week.

Furthermore, evidence has found that adults watched an average of 1,648 minutes (27.5 hours) of television per week in 2013.

Figures for England showed that almost two-thirds of adults and one-third of children aged two to 15 were overweight or obese.

In 1980, around 7% of adults were obese compared with around 25% today.

Dame Sally also used her study to call for more research into a potential link between deafness and blindness and dementia.

Data suggested a greater prevalence of dementia, including Alzheimer's disease, in those with severe vision loss or severe hearing impairment.

She also said England should explore the impact of minimum unit pricing for alcohol if Scotland introduced it.

Simon Gillespie, chief executive of the British Heart Foundation, said: "This report is yet another reminder that we can no longer turn a blind eye to the numbers on the scales.

"It's particularly troubling that around a third of children in the UK are now overweight or obese. Parents, schools and local communities all have a part to play to help kids reduce their risk of heart disease by eating well and keeping active.

"But the Government also needs to protect young hearts by stopping children being bombarded with junk food marketing. By placing a 9pm watershed on TV ads for junk food and regulating marketing tactics used to target kids online they can make it easier for families to eat healthily."

Professor Kevin Fenton, national director of health and wellbeing at Public Health England, said: "PHE welcome the Chief Medical Officer's report and we share her concerns on the normalisation of obesity and excessive alcohol intake.

"Overweight and obesity costs the NHS over £5 billion each year and is entirely preventable. PHE are committed to helping to tackle obesity through a range of approaches that support action on the local environment to make eating less and being more physically active, easier."

Tam Fry, from the Child Growth Foundation and the National Obesity Forum, said: " Having recently stated to the House of Commons health committee that she believes research will show that sugar is addictive and that taxing it may be required, the report lets the food and beverage industries off the hook.

"It makes no mention of sugar being addictive - which it is - and trots out the off-repeated Whitehall mantra that Government will legislate if excess sugar is not cut out of their products.

"It gives industry no deadline by which to show improvement with the likely result that her words will be quite ignored.

"How distressing."

Dame Sally pointed out that besides its other effects, alcohol was very calorific and she was concerned that Budget changes to alcohol duty - including a penny off a pint a beer - could encourage more drinking.

"Once I discovered the calories in alcohol, as well as the bad side effects, I drank much less," she told BBC Radio 4's Today.

"I worry that people will drink more but in fact at the moment alcohol consumption has not recently gone up, probably because of austerity."

People also needed to be made more aware that fruit juice was not a healthy option in large quantities," she said.

"When I used to sit in my clinic, mothers would bring their children in drinking vast amounts of orange juice and they thought this was healthy.

"Well one glass of orange juice in the day is but actually orange juice, and other juices, have a lot of sugar, natural sugar, and many calories.

"People need to think about this."

Shadow public health minister Luciana Berger said: "This report clearly illustrates the Government's failure to get to grips with the alarming rate of obesity.

"The Government should be on the side of parents in tackling this problem but they're failing. Their voluntary Responsibility Deal is weak and simply not working.

"Nothing is more important to any parent than protecting their child's health, yet the system is stacked against parents who want to make the right decisions for their children.

"The scale of the obesity challenge demands bold leadership. That is why Labour is consulting with parents and experts about whether a cap is needed on the amount of sugar, fat and salt in food marketed to children."